The present invention relates to an eyeglass lens processing apparatus for processing a periphery (an edge) of an eyeglass lens.
An eyeglass lens processing apparatus is available, which has a chamfering abrasive wheel for chamfering a lens corner portion after the lens periphery is subjected to processing with a rough abrasive wheel and a finishing abrasive wheel. An eyeglass lens processing apparatus having a grooving abrasive wheel is also proposed.
In case of processing a lens narrow in vertical width, such as a half-eye lens, the related eyeglass lens processing apparatus does not execute processing if an abrasive wheel interferes with a lens holding member during chamfering process, or only executes limited chamfering to such a degree as to avoid the interference. For this reason, the related eyeglass lens processing apparatus suffers from a problem in that a minimal processing diameter of a lens, which can be subjected to chamfering process, is large.
The related eyeglass lens processing apparatus controls an amount of chamfering by adjusting the number of rotation of the lens, and thus there are some cases that processing efficiency is not good.
Accordingly, an object of the present invention is to provide an eyeglass lens processing apparatus, which can efficiently execute chamfering process and which can make a minimal processing diameter of a lens as small as possible.
The present invention provides the followings:
(1) An eyeglass lens processing apparatus for processing a periphery of an eyeglass lens, comprising:
a lens rotating shaft which holds and rotates an eyeglass lens to be processed;
an abrasive wheel rotating shaft movable between a retracted position and a processing position;
a chamfering abrasive wheel which is attached to the abrasive wheel rotating shaft and which chamfers the lens while receiving a processing load from the lens during processing;
a detecting unit which detects the load to the chamfering abrasive wheel; and
a control unit which issues a control signal for relatively moving the lens and the chamfering abrasive wheel one from another to reduce the processing load if the detected processing load is higher than a predetermined first level and for continuing the chamfering, and which issues a control signal for ending the chamfering if the detected processing load over the entire periphery of the lens is lower than a predetermined second level.
(2) The eyeglass lens processing apparatus according to (1), wherein the control unit issues a control signal for ending the chamfering if a predetermined time period is elapsed or the lens is rotated predetermined number of times even in a case where the detected processing load over the entire periphery of the lens is not lower than the predetermined second level.
(3) The eyeglass lens processing apparatus according to (1), wherein the lens rotating shaft includes a first shaft having a cup holder to which a cup attached to the lens is to be attached, and a second shaft having a lens retainer to which a rubber member for abutting against the lens is fixed, and the first and second shafts are relatively moved one from another in a direction of a rotational axis thereof to clamp the lens therebetween.
(4) The eyeglass lens processing apparatus according to (1), further comprising:
a first moving unit having a motor, which relatively moves the lens rotating shaft and the abrasive wheel rotating shaft one from another to vary an axis-to-axis distance therebetween;
a second moving unit having a motor, which relatively moves the lens rotating shaft and the abrasive wheel rotating shaft one from another in a direction of a rotational axis thereof; and
wherein the control unit issues the control signal to at least one of the first and second moving unit to relatively move the lens and the chamfering abrasive wheel the one from the other.
(5) The eyeglass lens processing apparatus according to (1), further comprising:
a first rotating unit having a first motor, which rotates the lens wheel rotating shaft;
a second rotating unit having a second motor, which rotates the abrasive wheel rotating shaft; and
wherein the detecting unit detects a load electric current of at least one of the first and second motors.
(6) The eyeglass lens processing apparatus according to (5), wherein the predetermined second level includes an electric current value not higher than the predetermined first level.
(7) An eyeglass lens processing apparatus for processing a periphery of an eyeglass lens, comprising:
a lens rotating shaft which holds and rotates an eyeglass lens to be processed;
an abrasive wheel rotating shaft movable between a retracted position and a processing position;
a chamfering abrasive wheel which is attached to the abrasive wheel rotating shaft and which chamfers the lens while receiving a processing load from the lens during processing;
a detecting unit which detects the load to the chamfering abrasive wheel; and
a control unit which issues a control signal for relatively moving the lens and the chamfering abrasive wheel one from another to reduce the processing load if the detected processing load is higher than a predetermined first level and for continuing the chamfering, and which issues a control signal for ending the chamfering if the detected processing load over the entire periphery of the lens is lower than a predetermined second level,
wherein the control unit issues a control signal for ending the chamfering if a predetermined time period is elapsed or the lens is rotated predetermined number of times even in a case where the detected processing load over the entire periphery of the lens is not lower than the predetermined second level.
The present disclosure relates to the subject matter contained in Japanese patent application No. 2000-134335 (filed on Apr. 28, 2000), which is expressly incorporated herein by reference in its entirety.